The gravity flow of water within soil.

Same as fogbow.

A pointed device which indicates the amount of resistance encountered when it is forced into a material such as snow or soil. See ram penetrometer.

In general, the transformation of data from a "raw" form to some useable form. In meteorology, this often refers to the conversion of the observed value of an element to the value which it would theoretically have at some selected or standard level. The m ...

Psychrometer to which a small chain or rotary handle is attached so that the observer can rotate the instrument rapidly to properly ventilate the thermometer bulbs.

The audio-frequency signal transmitted by the Diamond-Hinman radiosonde when the baroswitch pen passes each fifteenth contact of the commutator, up to a number determined by the design of the commutator, and each fifth contact thereafter. This signal is t ...

The direction, with respect to true north, from which the wind is blowing. Distinguish from magnetic wind direction. In all standard upper-air and surface weather observations, it is true wind direction that is reported.

Programs or instructions which are stored in readonly memory.

Literally "not wet", containing no liquid.

Water vapor content of the air. See absolute humidity, dew point, mixing ratio, relative humidity, specific humidity.

A device for computing certain psychrometric data, usually the dew point and the relative humidity, from known values of the dry-bulb and wet-bulb temperatures and the atmospheric pressure. One type is the circular slide-rule form and, like the psychromet ...

A device for measuring sea-surface waves. It consists of a weighted pole below which a disk is suspended at a depth sufficiently deep for the wave motion associated with deepwater waves to be negligible. The pole will then remain nearly as if anchored to ...

Same as altimeter setting.

Facing away from the wind.

A wind blowing in the same direction as the heading of a moving object. thus assisting the object's intended progress. The opposite of a head wind.

An instrument which determines the black-body temperature of a substance by measuring its thermal radiation.

A unit of pressure which directly expresses the force exerted by the atmosphere. Equal to 1000 dynes/cm2 or 100 pascals.

A measure of the amount of "spin" (or rotation) in the atmosphere.

Same as river gauge.

Same as atmometer.